In The Martianthe character played by Matt Damon was forced to use his own feces to grow potatoes in the inhospitable Martian soil. The dust lacking nutrients prevents any plant from growing on it. That’s why he had to desperately obtain nutrients. In the future the story could try to replicate itself, but a team of German scientists has found a somewhat more elegant way to grow crops in the soil of Mars: using cyanobacteria as fertilizer.
A lifeless soil. The dust that covers the Martian soil, known as regolith, it is rich in mineralsbut it lacks the organic nutrients necessary for plants to grow on it. Therefore, if in the future an attempt was made to grow plants on Mars, it would be impossible.
The rest of the planet doesn’t help either.. Soil is not the only limiting factor for growing plants on Mars. The extreme temperatures, which can reach 60ºC, and the atmosphere composed mainly of carbon dioxide are not great incentives either. On the other hand, there is the lack of liquid water and cosmic radiation seriously endangers any known form of life.
The win win of agriculture. Growing food on Mars would be very advantageous for obvious reasons, such as feeding astronauts, but also because plants generate oxygen through photosynthesis. Considering how unbreathable the Martian atmosphere is, this would be very advantageous. The problem is that, to do so, it is not enough to use feces in the purest style of The Martian.
The enemy is on the ground. Martian regolith is known to be covered in perchloratestoxic salts that hinder plant growth at many levels. For example, they prevent germination and alter the metabolism of plants. Fortunately, it has been detected that there are specific points on the planet where the wind has caused the accumulation of gypsum, displacing perchlorates. Since there are plants that benefit from gypsum as a substrate, you could try growing them in those spots. The problem is that this solution greatly reduces the growing locations and plants that can be chosen.
A peculiar pantry. Many scientists have been researching for years ways to improve the diet of future space colonizers. If it cannot be grown directly in the ground, it will have to be done in the warehouses themselves. For example, already in 2015 lettuce was grown on the International Space Station. Much more recent is the cultivation of tomatoes on the Chinese space station Tiangong. In this case, has been achieved done in the air thanks to a technology that sprays water and nutrients in the form of mist to directly feed the roots of the plants. And if it’s complicated with plants, you can always resort to crickets. It is one of the bets for the future of the European Space Agency.
Cyanobacteria to the rescue. Cyanobacteria are capable of using the carbon dioxide so abundant in the Martian atmosphere to generate oxygen in a process in which nutrients can also be extracted from the mineral-rich dust of the Martian soil. For this reason, a team of scientists from the University of Bremen has tried using them as fertilizer.
To do this, once the cyanobacteria have been cultured, have resorted to anaerobic fermentation. This is carried out by inoculating bacteria that metabolize cyanobacterial biomass in the absence of oxygen. They are capable of growing in high concentrations of perchlorates and in the fermentation process they release very beneficial nutrients for plants, such as ammonium. In laboratory tests, in which this fertilizer was used to grow lentils, 27 grams of lentils were obtained from a single gram of cyanobacteria processed through fermentation.
By the way, a little fuel. In the fermentation process, methane is also released, which can be used as fuel. These are all advantages for a future colonization of Mars.
It’s not over yet. With this type of fertilizers, some of the barriers that prevent farming on Mars would fall. However, it should be noted that the study was carried out with a simulator of the Martian regolith, but without simulating the external conditions of the red planet. That is, neither extreme temperatures, low gravity nor cosmic radiation were taken into account. In the future it is hoped to test these cyanobacterial fertilizers again in a much better simulated environment. It is a necessary step so that there will truly come a day when food can be grown on Mars.
Image | The Martian
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